Slice the chicken breasts right through the centre to create 4 even-sized cutlets. Coat in salt, garlic powder, onion powder and black pepper.
Add around 1 tbsp olive oil to a large, deep pan over medium-high heat. Once hot, add the chicken and fry both sides for 3-4 minutes until golden and just about cooked through the centre. Remove and add to a side plate. Fry asparagus (if using) for a few mins with a good pinch of salt & pepper until they begin to soften. Add to the plate with the chicken and cover in foil to keep warm.
Reduce the heat to medium and melt 1 tbsp butter. Add the leek and fry until it softens and starts turning golden, then add in the garlic, thyme & lemon zest and fry for another minute or so. Stir in the orzo, then pour in chicken stock and the juice of half the lemon. Give it a stir, then stir in the cream and a good pinch of salt and pepper.
Give everything a stir, then bring it to a simmer. Cook the orzo, stirring frequently, until it's al dente and the sauce has thickened to a risotto-style consistency. Stir in the parmesan, then stir in 1 more tbsp butter until it melts and blends into the sauce.
Stir in the resting juices from the chicken, then slice it into thin strips. Taste-test the orzo and adjust with salt, pepper and more lemon juice if desired. If it overthickens, just stir in a splash more stock or hot water to thin it out as needed.
Serve individual portions with sliced chicken on top, alongside asparagus, a sprinkle of fresh parsley and a lemon wedge each (if you want it more lemony).